Three days after Vernon Davis said he planned to attend this week's mandatory three-day minicamp, the 49ers' tight end wrote an article Monday that suggests he'll remain absent from the team's facility.

In his role as a guest columnist for the MMQB website, Davis, who has not attended the team's voluntary offseason program, opened with a section titled "Why I'm Holding Out."

"It's all about getting paid what you deserve," Davis said. "It's not that complicated. I want the 49ers to win the Super Bowl, and I want to be on the field this summer working toward that goal, but I have to worry about my future first."

Davis, who played coy in late May about his reasons for not training with the 49ers this spring, eventually acknowledged that he had an issue with his contract, which expires after the 2015 season. His $7.35 million average annual salary over the life of his deal ranks third among tight ends, behind New England's Rob Gronkowski ($9 million through 2019) and Dallas' Jason Witten ($7.4 million through 2017).

Last season, Davis had 52 catches, 850 yards and accounted for 13 of Colin Kaepernick's 21 touchdown passes. His 13 TD receptions are tied for the third most by a tight end in an NFL season.

"In 2010, I signed a five-year, $37 million contract extension with $23 million guaranteed," Davis said. "It was the biggest contract for a tight end in league history. Four years later, and I'm playing at a higher level than I was then, which brings me to why I'm holding out."

On Friday, Davis said he expected to attend the three-day mandatory minicamp, which begins Tuesday.

"I plan on being there," he said on 95.7 FM.

Davis, who already forfeited a $200,000 workout bonus, would be fined nearly $70,000 if he doesn't attend the minicamp.

Niners right guard Alex Boone also has skipped the offseason program because of dissatisfaction with his contract. Boone is not expected to attend the minicamp, according to multiple reports.